There are many choices either new or used. A couple of things to look for is double pane windows and basement heat. If those two options are included you can feel somewhat comfortable that it is a four season rig. Keep in mind that each manufacturer will offer several versions of what they consider to be a four season coach but when you get to the specifics you will find different insulation ratings and materials that will make a difference.

If you are looking for something that will be used in extreme cold I also highly recommend a coach with the Aqua-Hot option. It is a spendy option but well worth it as far as I am concerned.

Our previous coach, 1991 Beaver Contessa, did fair in cold weather but when the temps would get down into the low 20's/high teens the furnace would run almost non-stop. In the seven years we had it we froze up once when the temperatures got down around 11 degrees once night. It took me a about an hour to thaw the line out in the morning with the wife's hair dryer.

In our current coach we have been in the single digits a couple of times with no problems and have stayed warm and comfortable inside.

I also forgot to mention, we survived -40° F for a couple of days in our Newmar Dutch Star. No freeze ups but it is an ordeal to keep things warm. We did use a lot of propane but I don't recall the actual quantities.

Our 2010 Bounder kept us through two very cold, blustery nights last February, minus 4º and minus 6ºF, at an Elephant Butte, NM RV park. Obviously we had the propane furnaces running all the time (went through nearly half a tank), along with a small electric heater. The rig had been winterized, but the fresh water and holding tanks are heated, in any case (not all the water lines, though). Showers were taken in the RV park's building (nice place).

We did close the slide on the second night, because of the noise from the slide topper in the strong winds, not because of being too cold (though it did give us less space to heat).

Another option is to search for a US made motorhome that from the frame up was built to be sold in Canada with the Canadian stickers and requirements which are different than the US or CA requirements. Check with the manufacturers of the rigs and floor plans you want and see if: 1: any of them that were built to Canadian spec and 2. sold in Canada are available now for sale, new or used and/or3. do they know of any imported back to the US?

I found and purchased a '94 Itasca Suncruiser 34RG DP built to all the above, sold by Guaranty in Edmonton and the last PO owned and maintained it Sault Ste. Marie MI. It has heated bays, thermopane windows, extra insulation, block heater and numerous changes to Canadian specs, all of which make it not only better unit IMO, but equip it also for the similarly harsh environment of the SW deserts. I've lived in AK and El Centro CA, so I know both.

This is not a comment about your motor home. However the principle we use may be of use to you or anyone else with the similar conditions.

We have Montana Model 3750FL (the one with the front living room and rear bedroom and bath). We use it all year around and have used it a number of times camping in below Zero weather.

When we camp over night in cold temps, ( we have been down to below Minus 20 (f) we slide in the two livingroom slides to reduce the interior space to heat overnight. Then, in the daytime, we slide in the two bedroom slides (since we don't need the bedroom in the day) to reduce the space to heat during the day.

The bathroom and kitchen remains open (the kitchen/dining area has one slide) day and night since all of the plumbing, etc is in those areas (which are actually heated by the furnace).

We have had not problems camping in cold weather and doing as explained above we feel that we keep more economically comfortable. We have sometims used the Living Room fireplace when it made the living room more comfortable with those slides out. Sometimes, during the day, (such as when we are parked for the day and will be out of the RV all day), we actually slide all of the 5 slides in to conserve heat until we return in the evening to use the RV when it is really cold outside.

Our configuration of the RV would not be available for many others but each person might consider the options available with their unit.

Certainly NOT Winnebago! They have increased the roof thickness recently, but that's it. Walls and floors are marginal R-values. I believe they increased the roof thickness due to pressure from some of us that had basement air cooling problems, and voiced these in various forums.